It's terrible. We have, what, seven billion people on earth? Now there's a population explosion and all of a sudden we have a trillion Scott Becquerels. They can't create Quantum Leap reboots fast enough, and everyone is scrambling to keep all Star Trek-related scripts away from them.

Depends. If you are a nuclear apologists, it is irrelevant. If you want real numbers, its a few 1000 more cases of cancer that unfortunately cannot be identified individually as having been caused by this.

However, one curie is an awful lot of radiation. You wouldn't go near that. On the other hand, becquerel and curie are measures of "radiation per hour", so "1 trillion becquerel released" doesn't make sense.

So instead of a pro-nuke justification put in terms of banana equivalent doses we get FUD with undefined threats against our lungs and other vital organs? You thought yourself better than the hypothetical poster you so fear?

agreed, the bequerel as a unit is bad enough, but it's even worse when people mis-use it. A bequerel isn't a count of something, like coulomb or joule (or "atoms popping tops off") but rather a rate, like amperes or watts. it's (atoms popping off) per second. so the notion of "bequerels per hour" makes no sense, or "a total of N bequerels".

the best you can do, if you want to measure the number of atoms blowing their wad over a period of time, you multiply the atoms-blowing-chunks-rate with the number of seconds in the time period. So, if something has a radioactivity of N bequerels, then there are 3600 * N atom pops per hour. Or, as we do with electricity, you could measure atomic pops with the unit bequerel-hours. You could also say "my atomic trash emitted N bequerels (or N/3600 bequerel-hours) over the course of the clean-up period.

honestly, the bequerel-hour may be the most common-sense method to measure radioactivity. It's grounded in the physical world (atomic pop-offs) unlike things like greys, and it's similar enough to watt-hour that people will use it right.

A dose released in a short amount of time is much more damaging than a dose released over a long period of time.If you have a high dose*time over a second, the body won't be able to heal itself.If you have the same dose over 10 years, your body can heal the damage.

Also, the Bq is a worthless unit because it doesn't tell you *what* is released.A decay that releases a low energy beta is fairly harmless, but if it releases a 10 MeV gamma, that is very bad.

A cubic kilometre of seawater contains about 10 trillion becquerels of the naturally-occurring potassium K-40 isotope. That's ten fucking disasters per cubic kilometre using your scale and there's a lot of seawater on this planet (1.3 billion cubic kilometres according to most sources).

Ten trillion nuclear disintegrations of potassium-40 occur in a cubic kilometre of seawater every second. A single nuclear disintegration per second is a becquerel (Bq). Usually Bq are qualified by being associated with a mass or volume, Bq/litre or Bq/kg. Radioactivity in seawater is usually measured in terms of litres but if you make the sample size big enough (cubic kilometres) the numbers can look really scary.

in miles per hour. No but seriously, Bq is disintegrations per second. It's a convenient way to quantify radiation if you have one isotope or it's contained in a small area, but is absolutely ass for a situation like this.

While it's not a good thing, using Becquerels is a convenient way to make something sound worse than it actually is. It's 27 Curies, which is about 0.18% of the activity of the sources they use for some gamma sterilization machines (which can be around 15000 Curies or 555,000,000,000,000 Bq). Now that is a scary amount of radiation.

The Curie is not an SI unit. It is, however, locked to the Becquerel by a fixed ratio. They measure exactly the same thing, so in what way do you claim Bq are "bad?" The GP seems to want a measure of disintegrations without regard to time, which makes zero sense. It's like claiming you did work or expended energy when trying to lift a 1 Kg rock with 1 N of force.

Even though they measure the same thing, the Becquerel is a very, very small unit. If somebody was talking about the risk of a dam breaking, and used the cubic centimeter for measuring the volume of water behind that dam, perhaps with a note that a single cc of water can killl a person if they choke on it just right as a justification, wouldn't you still prefer a unit such as gallons, or cubic feet or cubic meters, Wouldn't that be better in helping asses the real consequences of a dam failure even though we are measuring the same thing? Or wouldn't it be better to give information on just how many acres downstream would be flooded and how many people live on that floodplain, even though that's all a very different kind of measurement? There are plenty of cases where either a similar measurement that uses units more in keeping with the situation or a measurement of something different may either or both be better.
Using SI units is a good thing overall, but what if those units are many orders of magnitude outside of the thing they were designed to measure and there's a non-SI unit that isn't? Or, what's the point in preferring Km./liters over miles/gallon if we are talking about how much fuel it took to send Voyager 1 outside the heliopause? Neither one is very useful when we are not exactly sure just where the edge of the solar system is, or how to measure it, and Voyager will keep on coasting many light years farther in the end, if its trajectory even has an end in the lifetime of the universe.
I see using becquerels in this case as similar to someone being opposed to a government project, so they give how much it costs in the currency of some nation currently undergoing hyperinflation, so the project costs a bajillion, bajillion, Saganillion Elbonian Smerdlaps, That's not the same thing as writing about the US economy for a European audience and converting to Euros, or writing about the European economy for Japan and converting to Yen. Even though we know a conversion rate for the uints, and it's fixed as of a given date,,using some units for currency could still be an attempt to make the numbers sound so large they prejudice the average reader more than they inform. You should look at what level of information the average person reading an article from that particular source will have in deciding whether a difference of units is simply a difference or if there's some intent to mislead - and since you asked it as in what way X is:bad?", hopefully we can agree attempts to mislead are bad.

The units are not that important, what matters is the relative numbers. The point of the story is that TEPCO is failing to prevent the release of radioactive material from the plant in enough measure to contaminate nearby crops and make them worthless. Relatively speaking the amount of released material is lower now, but expected to rise once they start further decommissioning work.

In this case the unit used by TEPCO and the government is Becquerels, and there has been a great deal of discussion about it in

Perhaps I should have been more clear. I think it's a bad unit to use, because it's being used to purposefully scare people. The large order of magnitude of the measured values is misleading. Saying 1 Trillion Becquerels makes it sound a lot worse than it actually is.

The article was reporting on a relative increase, and actual harm. Radioactive material is normally being released to the atmosphere from the site at a rate of 10 MBq / hr. The article points out that there was some recent work which released it at a rate of 280 GBq / hr, over a period of 4 hours. That's 28,000X the normal rate (over 3 years' worth), and it resulted in radiation contaminated crops 20 km away.

I think his issue wasn't in the units but in the dimensional analysis. Its like saying "I walked a total of 3mph!" Uhhh.. total? You can't really compute a total of "X per unit time." At least not in any way that makes physical sense. You could add up all of the individual units (or integrate over it if you want to go continuous) but then you're effectively removing that "per unit time" bit and the original statement still doesn't make s

Bq seems a fair measure to me. It's a measure of radioactivity. Would you prefer pounds (or kilograms) of X, with no measure of the rate X is releasing radiation?

It's a bad unit to use in this context because it's a measure of individual atomic decays per second. It's kinda like you asking me how far you have to walk to get to the nearest bus stop and me telling you the distance in angstroms. The scale is just completely devoid of any common reference frame for the number to be intuitively useful (not that most people have a common reference frame for radioactivity). That's why Bq is commonly used by people trying to scare the public about radioactivity - when you're talking about a lot of material like, oh, a field, it results in really, really big numbers.

Let's put it this way. A block of soil one square mile by 1 foot deep (790,000 m^3) has a natural radioactivity of 653 billion Bq [isu.edu]. If they excavated 1.1 trillion Bq of radioactive material from Fukushima, then they removed about as much radioactive substances as is naturally contained in 1.7 square miles of soil one foot deep. Of course the piece of information that we're missing (and no it's not in TFA) is how much volume of material they removed. If we knew that, we could come up with a ratio and say "Ah hah! The stuff they removed is x times more radioactive than the natural radioactivity of dirt!"

It's worse than that it's like asking someone how far the bus stop is and the person answering 10mph.

I can't help but notice that the lack of any meaningful measurements was used by several slashdotters to say the radiation was low and then several modders conveniently overlooked the fact that their math made no sense whatsoever and modded them up because the message is pro-nuclear.

"It's kinda like you asking me how far you have to walk to get to the nearest bus stop and me telling you the distance in angstroms."

No, it isn't. Angstroms are not an SI unit. It's more like asking how far the next town is, and getting an answer in meters instead of km.

More like nanometers. Bq is measuring events on an atomic scale. nm is actually a little too big, but it is getting close.

When diluted into even a pond (let alone an ocean) trillions of Bq aren't actually all that much. People eat about 9 trillion Bq of potassium each year from bananas alone, so if humanity collectively drank the entire pacific ocean they might double their dose (and have one heck of a sewer bill).

The headline here was way off - this was over 1 TBq being release to the atmosphere recently over a single 4 hour period. It resulted in radioactive contamination of crops 20 km away. The total amount of radioactive material released from the site is obviously much, much greater.

As everyone else has said a milion times already, Bq is not a quantifiable "amount" of radiation, its a rate. You cannot release x Bqs in y period of time, any more than you can travel 50mph in 2 hours. You could say "I travelled 100 miles", or "I am currently travelling at 50mph", or "over 2 hours I averaged 50mph", but mph is not , itself, a quantity. Same with Bq.

From Wikipedia [wikipedia.org] One Bq is defined as the activity of a quantity of radioactive material in which one nucleus decays per second.

No, thats not what theyre saying:On Wednesday, Tokyo Electric Power Company presented the Nuclear Regulation Authority with an estimate that the removal work discharged 280 billion becquerels per hour of radioactive substances, or a total of 1.1 trillion becquerels.Theyre treating Bq as if its a quantity of radiation. They dont know what theyre talking about. They multiplied 280 billion by 4, and ended up with 1.12 trillion-- which isnt how rates work.

Except that they dont list what material they are talking about, and anyone who has done 5 minutes of research know that units like the Sievert and the Gray are far more useful when talking about human exposure, because they compensate for the different sorts of radiation and their effects.

Saying "1 curie" doesnt tell you much if you dont know what its 1 curies worth of, or how much total matieral we're talking about.

Conveniently, there is an even better comparison. You have to disperse all of the radioactive soil into the air to make a similar comparison. We don't actually pump soil into the air though. We do however burn coal.

Webpage [blogspot.com] According to the National Council on Radiation Protection and Measurements (NCRP), the average radioactivity per short ton of coal is 17,100 millicuries/4,000,000 tons, or 0.00427 millicuries/ton. This figure can be used to calculate the average expected radioactivity release from coal co

Can someone with experience comment on whether that is a lot or not? Obviously it's not what anyone wants released into the environment, but as a non-becquerel expert it's hard to have some sort of relevance.

Not that much. A typical Tc99m scan involves injection a bit over a billion (10E9) bq per person, albeit half life is only 6 hours. Reminds me of a "warning sticker" for a CB radio - "Danger 5,000 milliwatts".

This is a common misunderstanding of the way the released radioactive particles affect humans. The material from Fukushima bioaccumulates inside the body. It has already been found to be doing this in wildlife and people near the plant. Once inside the body's organs it can remain for decades, slowly damaging the DNA and leading to cancer. Things like x-rays are one-off events that deliver a single dose, much of which is blocked by tissue (that's why parts of the image are dark), this stuff bypasses all the

Yes, it is important. POTUS was able to name the one American that died on an airplane shot down over disputed territory only hours after it happened. Our modern society has access to information in detail and speed that is mind boggling. If Fukushima was the disaster that people claim it was then it would seem to me that we should be able to know the names, ages, places of residence, and specific cause of death of every person that died from that disaster. If someone cannot so much as give a name then

Or over a gram of radium, enough to cause massive skin ulceration after hours of exposure. You're correct it isnt much Caesium-137, but it's still enough to cause flesh to rot away from your body, in dense enough exposure. Experiment has shown 140MBq/kg of C137 to be fatal within 130 days. Half that, 1 year. So no thanks to being exposed to all 1 TBq of it.

* Comments by people providing definitions for what a Bq is, talking about equivalent measures, giving conversion forumulas, and providing hard facts; generally these are saying that the number is either irrelevant, and / or not really that big.

* Comments by people who are being quite vague, and warning of various undefined threats to various undefined organs because of how big the number is.

And mine wass an explanation that radioactivity without density is meaningless.
Hold a gram and change of radium in your pocket for a week and tell me 1 GBq is irrelevant. It wont kill you... well, maybe it will after long enough, but it will cause the flesh to fall off. A gram of radium spread out over a square mile? not such a big deal.

For your information, an average human body contains natural radioactive isotope of potassium - 40K. Every second there are approx.
3000 decays (Bq) of that isotope in your body. It means that every man is approx. 9 billions Bq "on release" per year. 40K emits 1460 keV gamma-ray (that easily goes out of your body) in about 10% of decays, the rest ends in beta-particle only, that stays inside. That's one of the problems of measuring release in Bq, which is not a good idea.
Anyway, your one trillion Bq is e

Now that the Slashdot Pundits have made fun of a number, here's what's happening in the real world.

According to researchers, monkeys in the vicinity of Fukushima City had detectable levels of radioactive cesium in their muscles, while the northern monkeys did not. Researchers also found that the Fukushima simians had significantly lower white and red blood cell counts compared with macaque troops almost 200 miles away.

The researchers suggested their findings mirrored studies conducted on human health impacts following the Chernobyl disaster, where researchers found decreased blood cell counts in people living in contaminated areas.

The Chernobyl site is in the process of having a New Safe Confinement [wikipedia.org] structure built, which will keep radioactive material from the disaster site from entering the environment for 100 years. Once it is in place some of the radioactive material will be broken up and moved to long term buried storage.,

In contrast, one of the articles states "The plant is believed to be still releasing an average of 10 million becquerels per hour of radioactive material." The quoted 1.1 trillion BQ figure was the result from recent debris removal.

Up to 1.12 trillion becquerels of cesium was dispersed last summer as debris was removed from the battered building of reactor 3 at the Fukushima No. 1 nuclear plant, with tainted rice later being found in Miniamisoma, Fukushima Prefecture, according to Tokyo Electric.

The amount of cleanup and debris handling remaining is immense compared to the work done in this last operation. This means that the impact of future work will be proportionally larger.

Beyond that, the three damaged cores are still not stable or safe. There is no solid information on the state of cores, or even if the core material is in the containment structure. At least one of the cores is believed to have suffered a complete meltdown and become corium [wikipedia.org].

The already severely damaged reactors are still at risk for future earthquakes, tsunamis and typhoons. Any one of these events could result in another large scale radiation event. The Fukushima disaster is not necessarily over. It's just less active.

So go on and giggle over a number. It shows that you have the collective intelligence of a retarded 11 year old.

Thanks. The comments on every single nuclear story on Slashdot seem to miss the point entirely. The units are just a way to measure the relative efficiency of the work being done to prevent leakage. The effects are observable, there is no need to guess based on the numbers. This is apparently too complex for most commentators to understand:-(

To suggest that critiquing a stupid unit of measure is somehow trivializing the problem is itself a strawman.

If I said that I'm 1,930,400,000,000 picometers tall, people SHOULD mock me for using a stupid unit of measure. When people are primed to overreact to an event like Fukushima and then confronted by a number in public reporting that uses just such an inappropriate unit of measure, one can either mock the report for being foolish, or condemn it for being deliberately i

Not to trivialize Fukushima Daiichi but the current release of 10 MBq/h could be compared to the single dose of 33 MBq my baby daughter has injected last week. I was not happy with that because it seemed that the examination was for no useful purpose.

Still, the Fukushima mess has convinced me that nuclear power is a too dangerous path to thread. Unfortunately.

Yeah, yeah, Tc-99m. I know. It was probably gone much earlier than that because we kept her plenty hydrated and it was chelated as the dimercapto succinicate which is eliminated in the urine. And yes, the radiation is mostly benign gamma that escapes.

Similarly, apparently what gives the Japanese the most trouble at Fukushima Daiichi (as far as I understand) is tritium which is very hard to capture in waste water but luckily decays through a very low energy beta.

By "a mess" I meant the fact that what was supposed to be inside the fuel rods came to the outside. That's plenty of a mess for me;-)

I am not going to check your numbers but it sounds awfully little. Actually, I did check your number for Cs and I get 0.311 g assuming a half-life of 30 years and 6*10^23 for Avogadro's constant. Pretty impressive clean-up.

My vague understanding of this clean-up is that they have enormous amounts of cooling water that has been in direct cont

Right, that's what I forgot. You're correct that Tritium originates from reactor operations, not radioactive decay after the accident had occurred, but in LWRs it appears to be a by-product of fission reactions (1 in 10000).

Well, there is a little deuterium in the water to start with but on top of that we have so many tons of water in an intense neutron flux for 40 years. Without trying to run the numbers, I am sure there is going to be a fair amount of tritium present.

Anyhow, I also just learned about the pathway to tritium in fission yesterday. Great, I learned something new.

Before I sign off from this thread: Do you know of a good, authoritative account of the Fukushima event? I heard rumours that the Tepco crew made some u

Before I sign off from this thread: Do you know of a good, authoritative account of the Fukushima event?

I don't, sorry. I find that there's tons of misinformation and downright falsehood about the event out there, both by tepco and anti-nuke activists,

Right, that's what I have found as well.

and I'm not gonna waste my time plowing through it and fact-checking every single line. I'm a technologist and as such much rather concern myself with the technology of newer safer and cleaner nuclear power than with politics.

Peace, man!

I just wanted to know if you had found something. You seemed very well informed.

Now lets use my favourite dosage level, and all radiation related matters should be in the everyday standard of BED (Banana Equivalent Dose)

We are talking about an exposure of 8,461,539 KG's of Bananas. Or about One 17th the level that Bananas expose humans to in a year. (@140Bqs per KG)

Did you know that Humans are radioactive and rated at about 100Bqs per KG, so we are talking about a release of radiation equal to about 11 million KGS of ppl or less than what the ppl in a city with around 180,000 populatio

Becquerels are tiny units. In the first 3 months after the accident 14 Quadrillion (1.5x10^16) becquerels were released. For comparison Chernobyl released 14 Quintillion (1.4x10^19) becquerels in total. (source [nature.com]).

Compared to that, 1 trillion (1.1x10^12) becquerels is a big improvement in rate of release and according to Wolfram Alpha [wolframalpha.com] represents around 300mg of Cs-137.

One Becquerel means one decay per second. So Fukushima each month emits radioactive material that adds additional 1 million decays per second to the environment.

This is a very small number, the natural activity of radioactive materials inside a human body is about 10000 Bq. One gram of radium is 37 billions Becquerels. So the whole Fukushima disaster emitted the equivalent of about 30 grams of radium, not a trivial amount anymore, but still very small on the global scale. For comparison, one ton of uranium-bearing minerals contain about 0.1g of radium.